Comparison of C-, N-, and O-Incorporated Non-blistering PECVD Si Films for Application in SiO_x-Based Passivating Contacts for Si Solar Cells

For application in high-efficiency silicon solar cells bearing SiOx-based passivating contacts, we have developed 100 nm thick, PECVD Si-rich amorphous films, capable of being processed in industrial furnaces without blistering, by incorporating adequate amounts of each of C, N, and O in the films during PECVD. We found that non-blistering of the films is a result of the low intrinsic stress (compressive) in the films and not due to a low H content, which, in fact, is much higher in the non-blistering films than in the C-, N-, and O-free films. Among the three types of non-blistering Si-rich amorphous films, we conclude that the O-incorporated one is the most suitable for application in SiOx-based passivating contacts owing to the film's high excess Si content and ability to crystallize.